U.S. Pat. No. 4,063,220, which issued Dec. 13, 1977, entitled "Multipoint Data Communication System With Collision System With Collision Detection", discloses a bit serial receiver network continuously connected to a plurality of communicating devices. Such is accomplished by forming the network of any one of a plurality of transmitting media, such as coaxial cable, optical fiber or other, connected together into one branched network by constantly active devices, like repeaters, by which communications necessarily adapted to one medium are translated into another medium. The patent further goes on to state that distributed along the communicating cable network are a plurality of stations, each including a using device generally categorized as either a computer, an auxiliary memory, or an input/output terminal. Each using host device, whether it be a computer or a remote terminal, is tied to the coaxial cable by way of a T-connector, or tap, connecting to a transceiver in series with an interface stage which in turn connects to the using device.
Three signals (transmit, receive, and collision) and power are transferred through the drop cable which connects the host equipment with the transceiver module. Host generated transmit signals are transferred to the transceiver. Transceiver generated receive and collision signals are transferred to the host equipment. Power for energizing the transceiver circuitry is transferred from the host source.
The system described is generally now publicly known as an Ethernet connection which, as set forth above, employs a drop cable between the transceiver module and the user host equipment. The transceiver module is attached to the Ethernet coaxial cable. User host equipment is a terminal, personal computer, workstation, printer, file server, gateway, etc.
The power, as set forth above, is provided to the transceiver module by the host equipment. However, the voltage supplied by said host could be within a range of voltages, typically between 11 volts DC and 16 volts DC, but the output power to drive the transceiver circuitry within the module must be voltage regulated and electrically isolated from the host source. A typical output voltage could be, for example, 9 volts DC. In addition, the Ethernet coaxial cable must be electrically isolated from host voltage references. Since the Ethernet cable is, by its very nature, a medium distance wire connection between remote operating host stations, reference voltage surges, or spikes, are typical and must be accounted for, or the voltage surge could, at worst, destroy the operating host unit, or, at best, cause a loss of data at the host station.
With the advent of LSI (large scale integrated circuitry), the transceiver module circuitry does not require as much power in the past and does not need to take up as much space as previous transceiver modules. Thus, the present invention discloses the use of an off-the-shelf switching regulator with accompanying circuitry to utilize a variable existing input voltage and produce a regulated output voltage. The present invention utilizes fewer parts than known similar power converters, soft start threshold provisions, overload protection, and LED (light emitting diode) performance indicator, and a trimmer for precise output voltage adjustment .